Effect of candesartan on progression and regression of retinopathy in type 2 diabetes (DIRECT-Protect 2): a randomised placebo-controlled trial

The retinal renin-angiotensin system: roles of angiotensin II and aldosterone

In the present review we examine the experimental and clinical evidence for the presence of a local renin-angiotensin system within the retina. Interest in a pathogenic role for the renin-angiotensin system in retinal disease originally stemmed from observations that components of the pathway were elevated in retina during the development of certain retinal pathologies. Since then, our knowledge about the contribution of the RAS to retinal disease has greatly expanded. We discuss the known functions of the renin-angiotensin system in retinopathy of prematurity and diabetic retinopathy. This includes the promotion of retinal neovascularization, inflammation, oxidative stress and neuronal and glial dysfunction. The contribution of specific components of the renin-angiotensin system is evaluated with a particular focus on angiotensin II and aldosterone and their cognate receptors. The therapeutic utility of inhibiting key components of the renin-angiotensin system is complex, but may hold promise for the prevention and improvement of vision threatening diseases.

Phase I trial of gemcitabine and candesartan combination therapy in normotensive patients with advanced pancreatic cancer: GECA1

Our retrospective study showed inhibition of the renin-angiotensin system was associated with better outcomes in patients with advanced pancreatic cancer receiving gemcitabine. The primary objective of this phase I study was to determine the recommended dose of candesartan in combination with gemcitabine in normotensive patients with advanced pancreatic cancer. Candesartan was given orally at an escalating dose (4, 8, 16, and 32 mg) q.d. daily, and gemcitabine was given 1000 mg/m(2) 30 min i.v. on days 1, 8, and 15, repeated every 4 weeks. Dose-limiting toxicity (DLT) was defined as grade 4 hematological toxicities, grade 2 hypotension, abnormal creatinine or potassium, and grade 3 or 4 other non-hematological toxicities. A standard "3+3" phase I dose-escalation design was used. A total of 14 patients (candesartan 4 mg, three patients; 8 mg, three patients; 16 mg, six patients; 32 mg, two patients) were enrolled. One of six patients at 16 mg showed DLT of grade 4 neutropenia and two of two patients at 32 mg showed DLT of grade 2 hypotension. Response rate and disease control rate were 0% and 79%, respectively. Progression-free survival and overall survival were 7.6 and 22.9 months, respectively. Candesartan 16 mg is the recommended dose in combination with gemcitabine in the treatment of advanced pancreatic cancer. (UMIN CTR: UMIN000002152).

Risk factors for progression of diabetic retinopathy in Alberta First Nations communities

OBJECTIVE

The Screening for Limb, I-Eye, Cardiovascular, and Kidney Complications (SLICK) Program was implemented in 1999 to improve diabetic care for Alberta First Nations individuals living on reserve. The purpose of this review is to determine the rate and predictors of progression of diabetic retinopathy (DR) over a 10-year period.

DESIGN

Cohort study.

PARTICIPANTS

Nine hundred and eighty First Nations patients with diabetes that underwent at least 2 teleophthalmology examinations during the study period.

METHODS

Patients underwent serial laboratory testing, and stereoscopic, mydriatic, retinal photography. Modified Early Treatment Diabetic Retinopathy Study grading of retinal images was performed via teleophthalmology. Progression was defined as an increase of 2 or more steps on the Diabetes Control and Complications Trial classification.

RESULTS

At baseline, most patients had no diabetic retinopathy (n = 777, 79.3%) whereas 203 people (20.7%) had either nonproliferative DR (n = 179, 18.3%) or proliferative DR (n = 24, 2.5%). Two-step progression occurred in 163 patients (16.6%), with only a minority of these individuals progressing to proliferative DR (n = 23). The median time to progression was 7.6 years. Multivariate Cox regression demonstrated that elevated hemoglobin A1C (hazard ratio [HR] = 1.42; p < 0.0001) and systolic blood pressure (HR = 1.24 per 10 mm Hg; p = 0.009) were independent predictors of progression of DR.

CONCLUSIONS

This population-based study has shown that the rate and predictors of progression of DR among First Nations individuals parallels non-First Nations populations, with HbA1C and systolic blood pressure being the strongest predictors. These findings suggest that targeted, individualized care to reduce blood pressure and control blood sugars could reduce progression of diabetic retinopathy, and possibly blindness in First Nations individuals living on reserve.

QALY weights for diabetic retinopathy--a comparison of health state valuations with HUI-3, EQ-5D, EQ-VAS, and TTO

OBJECTIVE

To estimate quality-adjusted life-year weights for patients with diabetic retinopathy by using various methods and to investigate the empirical validity of the different measures.

METHODS

The study population comprised 152 patients with diabetes in Östergötland County, Sweden. Participants were interviewed by telephone by using the time trade-off (TTO) method and a visual analogue scale (EQ-VAS) (direct valuations) as well as the EuroQol five-dimensional questionnaire (EQ-5D) and the health utilities index mark 3 (HUI-3) (indirect valuations). The quality-adjusted life-year weights were adjusted for potential confounders by using analysis of covariance. The empirical validity of the measures was examined by testing their ability to detect hypothetical differences between severity levels of diabetic retinopathy and by investigating the correlation between the measures and the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25).

RESULTS

All measures detected significant differences in scores between patient groups classified according to visual impairment in the better eye (analysis of covariance, P < 0.05), but only HUI-3 and EQ-VAS detected significant differences between patient groups classified according to visual impairment or pathological progression in the worse eye. HUI-3 recorded a difference of 0.43 in values between normal vision and blindness in the better eye, which was more than twice the differences captured by the other measures (0.15-0.20). In addition, HUI-3 showed the highest correlation with NEI VFQ-25 (r = 0.54; P < 0.001).

CONCLUSIONS

In cost-utility analyses, the choice of quality-adjusted life-year measure may affect whether an intervention is considered cost-effective. Furthermore, if decisions are to be based on values from the general public, HUI-3 can be recommended for cost-utility analyses of interventions directed at diabetic retinopathy.

Candesartan, an angiotensin II type 1 receptor antagonist, inhibits pathological retinal neovascularization by downregulating VEGF receptor-2 expression

Several studies have examined the anti-angiogenic effects of angiotensin II type 1 (AT(1)) receptor antagonists; however, the mechanisms underlying these effects are currently unclear. In the present study, we examined the efficacy and the mechanism of candesartan, an AT(1) receptor antagonist, in suppressing pathological retinal neovascularization. We used an in vivo murine oxygen-induced retinopathy (OIR) model and also studied the in vitro proliferation and migration of human retinal microvascular endothelial cells (HRMECs) induced by vascular endothelial growth factor (VEGF)-A. The regulation of angiogenesis-associated genes such as hypoxia-inducible factor (HIF-1α), VEGF-A, VEGF receptor-1, and VEGF receptor-2 was evaluated with real-time RT-PCR in the OIR model. In the OIR model, candesartan suppressed the pathological neovascularization in a dose-dependent manner, but did not prevent the physiological angiogenesis. However, candesartan did not inhibit VEGF-A-induced proliferation or migration in HRMECs in the in vitro study. When administered interperitoneally in the OIR model, candesartan reduced the upregulation of VEGF receptor-2 in the retina, but had no effects in the other angiogenesis-related genes, such as HIF-1α, VEGF-A, and VEGF receptor-1. These findings indicate that candesartan inhibited the retinal pathological neovascularization, at least in part, by suppressing the expression of VEGF receptor-2, independent of VEGF signaling cascade. Therefore, candesartan may be a useful therapeutic target for the inhibition of retinal neovascularization that has a low risk of serious side effects.

Renin-Angiotensin system hyperactivation can induce inflammation and retinal neural dysfunction

The renin-angiotensin system (RAS) is a hormone system that has been classically known as a blood pressure regulator but is becoming well recognized as a proinflammatory mediator. In many diverse tissues, RAS pathway elements are also produced intrinsically, making it possible for tissues to respond more dynamically to systemic or local cues. While RAS is important for controlling normal inflammatory responses, hyperactivation of the pathway can cause neural dysfunction by inducing accelerated degradation of some neuronal proteins such as synaptophysin and by activating pathological glial responses. Chronic inflammation and oxidative stress are risk factors for high incidence vision-threatening diseases such as diabetic retinopathy (DR), age-related macular degeneration (AMD), and glaucoma. In fact, increasing evidence suggests that RAS inhibition may actually prevent progression of various ocular diseases including uveitis, DR, AMD, and glaucoma. Therefore, RAS inhibition may be a promising therapeutic approach to fine-tune inflammatory responses and to prevent or treat certain ocular and neurodegenerative diseases.

Increases of vitreous monocyte chemotactic protein 1 and interleukin 8 levels in patients with concurrent hypertension and diabetic retinopathy

PURPOSE

To investigate whether concurrent hypertension affects vitreous cytokine levels in diabetic retinopathy.

METHODS

Vitreous samples from 41 patients with diabetic retinopathy with or without concurrent hypertension, who underwent vitrectomy, were collected. Vitreous cytokine concentrations were simultaneously measured using flow cytometry. Patients were stratified according to hypertension or other clinical conditions, and the differences in vitreous levels of monocyte chemotactic protein 1, interleukin 8, vascular endothelial growth factor, interferon-inducible protein 10, and monokine induced by interferon gamma were examined.

RESULTS

Vitreous levels of monocyte chemotactic protein 1 and interleukin 8 were significantly (P < 0.05) higher in hypertensive patients than in nonhypertensive patients and were significantly (P < 0.05) higher in active diabetic retinopathy than in inactive diabetic retinopathy. Vitreous levels of vascular endothelial growth factor, interferon-inducible protein 10, and monokine induced by interferon gamma were not affected by the coexistence of hypertension. In multivariate models, active diabetic retinopathy (P = 0.004 and P = 0.007), systolic blood pressure (P = 0.039 and P = 0.041), and hypertension (P = 0.032 and P = 0.035) were significant and independent predictors for increased vitreous monocyte chemotactic protein 1 and interleukin 8 levels.

CONCLUSION

Both monocyte chemotactic protein 1 and interleukin 8 levels were elevated in the vitreous of patients with diabetic retinopathy and concurrent hypertension. These findings may help to explain the epidemiologic and clinical evidence that systemic hypertension exacerbates diabetic retinopathy.

Interventions for age-related visual problems in patients with stroke

BACKGROUND

The prevalence of eye problems increases with age and, consequently, so does the level of visual impairment. As the incidence of stroke also increases with age, a significant proportion of stroke patients will have age-related visual problems. It is possible that the effect of interventions for age-related visual problems may differ in the population of stroke patients compared to the wider population of older people. The interaction between the problems arising directly from stroke and those arising directly from age-related visual problems will be complex. Interventions for age-related visual problems may also be affected by the presence of other stroke-related co-morbidities. Consequently, the nature and outcome of interventions for age-related visual problems may be different in patients with stroke.

OBJECTIVES

The aim of this review is to determine if interventions for age-related visual problems improve functional ability following stroke.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (March 2011), the Cochrane Eyes and Vision Group Trials Register (December 2009) and nine electronic bibliographic databases including: the Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 1), MEDLINE (1950 to February 2011), EMBASE (1980 to February 2011), CINAHL (1982 to February 2011), AMED (1985 to February 2011) and PsycINFO (1967 to February 2011). We also searched reference lists and trials registers, handsearched journals and conference proceedings, and contacted experts.

SELECTION CRITERIA

Randomised trials in adults after stroke, where the intervention is specifically targeted at assessing, treating or correcting age-related visual problems, or improving the ability of the patient to cope with visual impairment. Primary outcome was functional ability in activities of daily living and secondary outcomes included functional ability in extended activities of daily living, visual acuity, visual field, visual function, balance, falls, depression and anxiety, discharge destination/residence after stroke, quality of life and social isolation, adverse events and death.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened abstracts and planned to extract data and appraise trials. We planned that assessment of methodological quality would be undertaken for allocation concealment, blinding of outcome assessor, method of dealing with missing data and other potential sources of bias.

MAIN RESULTS

We considered 7357 titles, 460 abstracts and 85 full papers. We identified no studies for inclusion in this review.

AUTHORS' CONCLUSIONS

There are no implications for practice arising from this review. Evidence relating to the management of patients (from the general population) with age-related visual problems is available from other Cochrane reviews and is likely to be the best evidence available for making treatment decisions about individual patients. Subgroup analyses within these reviews to explore the effect of interventions for age-related visual problems in patients with stroke are recommended. We recommend that the objectives and selection criteria for this Cochrane review are amended and clarified prior to any future updates.

Reno-protective effects of renin-angiotensin system blockade in type 2 diabetic patients: a systematic review and network meta-analysis

AIMS/HYPOTHESIS

This meta-analysis aimed to compare the renal outcomes between ACE inhibitor (ACEI)/angiotensin II receptor blocker (ARB) and other antihypertensive drugs or placebo in type 2 diabetes.

METHODS

Publications were identified from Medline and Embase up to July 2011. Only randomised controlled trials comparing ACEI/ARB monotherapy with other active drugs or placebo were eligible. The outcome of end-stage renal disease, doubling of serum creatinine, microvascular complications, microalbuminuria, macroalbuminuria and albuminuria regression were extracted. Risk ratios were pooled using a random-effects model if heterogeneity was present; a fixed-effects model was used in the absence of heterogeneity.

RESULTS

Of 673 studies identified, 28 were eligible (n = 13-4,912). In direct meta-analysis, ACEI/ARB had significantly lower risk of serum creatinine doubling (pooled RR = 0.66 [95% CI 0.52, 0.83]), macroalbuminuria (pooled RR = 0.70 [95% CI 0.50, 1.00]) and albuminuria regression (pooled RR 1.16 [95% CI 1.00, 1.39]) than other antihypertensive drugs, mainly calcium channel blockers (CCBs). Although the risks of end-stage renal disease and microalbuminuria were lower in the ACEI/ARB group (pooled RR 0.82 [95% CI 0.64, 1.05] and 0.84 [95% CI 0.61, 1.15], respectively), the differences were not statistically significant. The ACEI/ARB benefit over placebo was significant for all outcomes except microalbuminuria. A network meta-analysis detected significant treatment effects across all outcomes for both active drugs and placebo comparisons.

CONCLUSIONS/INTERPRETATION

Our review suggests a consistent reno-protective effect of ACEI/ARB over other antihypertensive drugs, mainly CCBs, and placebo in type 2 diabetes. The lack of any differences in BP decrease between ACEI/ARB and active comparators suggest this benefit is not due simply to the antihypertensive effect.

Angiotensin II modulates VEGF-driven angiogenesis by opposing effects of type 1 and type 2 receptor stimulation in the microvascular endothelium

Vascular endothelial growth factor (VEGF) is a main stimulator of pathological vessel formation. Nevertheless, increasing evidence suggests that Angiotensin II (Ang II) can play an augmentory role in this process. We thus analyzed the contribution of the two Ang II receptor types, AT(1)R and AT(2)R, in a mouse model of VEGF-driven angiogenesis, i.e. oxygen-induced proliferative retinopathy. Application of the AT(1)R antagonist telmisartan but not the AT(2)R antagonist PD123,319 largely attenuated the pathological response. A direct effect of Ang II on endothelial cells (EC) was analyzed by assessing angiogenic responses in primary bovine retinal and immortalized rat microvascular EC. Selective stimulation of the AT(1)R by Ang II in the presence of PD123,319 revealed a pro-angiogenic activity which further increased VEGF-driven EC sprouting and migration. In contrast, selective stimulation of the AT(2)R by either CGP42112A or Ang II in the presence of telmisartan inhibited the VEGF-driven angiogenic response. Using specific inhibitors (pertussis toxin, RGS proteins, kinase inhibitors) we identified G(12/13) and G(i) dependent signaling pathways as the mediators of the AT(1)R-induced angiogenesis and the AT(2)R-induced inhibition, respectively. As AT(1)R and AT(2)R stimulation displays opposing effects on the activity of the monomeric GTPase RhoA and pro-angiogenic responses to Ang II and VEGF requires activation of Rho-dependent kinase (ROCK), we conclude that the opposing effects of the Ang II receptors on VEGF-driven angiogenesis converge on the regulation of activity of RhoA-ROCK-dependent EC migration.

Mortality rates in trials of subjects with type 2 diabetes

BACKGROUND

In randomized controlled trials (RCTs) of subjects with type 2 diabetes mellitus, mortality rates vary substantially. We sought to examine the inclusion and exclusion criteria of these RCTs to explore relationships with mortality.

METHODS AND RESULTS

MEDLINE database was searched from August 1980 through March 2011. Selection criterion included published RCTs of adults with type 2 diabetes mellitus of at least 1000 patients, reporting all-cause mortality and having follow-up duration of at least 1 year. Twenty-two trials were eligible. Annualized mortality rates were derived. Inclusion and exclusion criteria were tabulated for each trial. Trials were categorized in 4 groups according to annual mortality rates: <1, ≥1 to <2, ≥2 to <4, and ≥4 per 100 patient-years. The analysis cohort included 91842 patients and 6837 deaths. Mortality rates ranged from 0.28 to 8.24 per 100 patient-years. Patients enrolled in the highest mortality category were more likely to be older and had longer diabetes duration and higher blood pressure. The selection for hypertension was common in the low- as well as high-mortality trials. Although the mortality rates were higher in RCTs with prior cardiovascular morbidity, the selection for chronic kidney disease-defined by either higher serum creatinine or lower estimated glomerular filtration rate and/or the presence of proteinuria-was associated with the highest mortality rates.

CONCLUSIONS

In this analysis of RCTs of type 2 diabetes mellitus, a 29-fold difference in annualized mortality was observed. In these RCTs, selection for renal disease, defined by either decline in renal function or presence of proteinuria, portends important mortality risk. (J Am Heart Assoc. 2012;1:8-15.)

CLINICAL TRIAL REGISTRATION

URL: http://www.ClinicalTrials.gov. Unique identifier: NCT00303979.

Neovascularization is attenuated with aldosterone synthase inhibition in rats with retinopathy

Neovascularization is a hallmark feature of retinopathy of prematurity and diabetic retinopathy. Type 1 angiotensin receptor blockade reduces neovascularization in experimental retinopathy of prematurity, known as oxygen-induced retinopathy (OIR). We investigated in OIR whether inhibiting aldosterone with the aldosterone synthase inhibitor FAD286 reduced neovascularization as effectively as angiotensin receptor blockade (valsartan). OIR was induced in neonatal Sprague-Dawley rats, and they were treated with FAD286 (30 mg/kg per day), valsartan (10 mg/kg per day), or FAD286+valsartan. The cellular sources of aldosterone synthase, the mineralocorticoid receptor, and 11β-hydroxysteroid dehydrogenase 2 were evaluated in retinal cells involved in neovascularization (primary endothelial cells, pericytes, microglia, ganglion cells, and glia). In OIR, FAD286 reduced neovascularization and neovascular tufts by 89% and 67%, respectively, and normalized the increase in vascular endothelial growth factor mRNA (1.74-fold) and protein (4.74-fold) and was as effective as valsartan and FAD286+valsartan. In retina, aldosterone synthase mRNA was reduced with FAD286 but not valsartan. Aldosterone synthase was detected in microglia, ganglion cells, and glia, whereas mineralocorticoid receptor and 11β-hydroxysteroid dehydrogenase 2 were present in all of the cell types studied. Given the location of aldosterone synthase in microglia and their contribution to retinal inflammation and neovascularization in OIR, the effects of FAD286 on microglial density were studied. The increase in microglial density (ionized calcium binding adaptor protein 1 immunolabeling) in OIR was reduced with all of the treatments. In OIR, FAD286 reduced the increase in mRNA for tumor necrosis factor-α, intercellular adhesion molecule 1, vascular cell adhesion molecule 1, and monocyte chemoattractant molecule 1. These findings indicate that aldosterone inhibition may be a potential treatment for retinal neovascularization.

Prevalence, risk factors and complications associated with type 2 diabetes in migrant South Asians

It is estimated that type 2 diabetes (T2D) currently affects about 246 million people worldwide, with South Asians, especially Indians, having both the largest number of cases and the fastest growing prevalence. South Asian ethnicity has been identified as a major risk factor for the development of T2D with central adiposity, insulin resistance and an unfavourable lipid profile being identified as predominant signals of alarm. Leading databases, including Web of Science, Medline, PubMed and Science Direct, were consulted and manual searches were conducted for cited references in leading diabetes-related journals. In all, 152 articles were included for the final assessment reported in this review. Genetic predisposition, central adiposity and unfavourable lifestyle, including physical inactivity and an unhealthy diet, were associated with the prevalence of T2D in migrant South Asians. 'Westernization', acculturation, socio-economic factors and lack of knowledge about the disease have also been identified as contributors to the development of T2D in this population. Higher prevalence of T2D in migrant South Asians may not be entirely attributed to genetic predisposition; hence, ethnicity and associated modifiable risk factors need further investigation. Preventive measures and appropriate interventions are currently limited by the lack of ethnic-specific cut-off points for anthropometric and biological markers, as well as by the absence of reliable methods for dietary and physical activity assessment. This article describes the prevalence rate, risk factors and complications associated with T2D in migrant South Asians living in different countries.

Differential clinical profile of candesartan compared to other angiotensin receptor blockers

The advantages of blood pressure (BP) control on the risks of heart failure and stroke are well established. The renin-angiotensin system plays an important role in volume homeostasis and BP regulation and is a target for several groups of antihypertensive drugs. Angiotensin II receptor blockers represent a major class of antihypertensive compounds. Candesartan cilexetil is an angiotensin II type 1 (AT[1]) receptor antagonist (angiotensin receptor blocker [ARB]) that inhibits the actions of angiotensin II on the renin-angiotensin-aldosterone system. Oral candesartan 8–32 mg once daily is recommended for the treatment of adult patients with hypertension. Clinical trials have demonstrated that candesartan cilexetil is an effective agent in reducing the risk of cardiovascular mortality, stroke, heart failure, arterial stiffness, renal failure, retinopathy, and migraine in different populations of adult patients including patients with coexisting type 2 diabetes, metabolic syndrome, or kidney impairment. Clinical evidence confirmed that candesartan cilexetil provides better antihypertensive efficacy than losartan and is at least as effective as telmisartan and valsartan. Candesartan cilexetil, one of the current market leaders in BP treatment, is a highly selective compound with high potency, a long duration of action, and a tolerability profile similar to placebo. The most important and recent data from clinical trials regarding candesartan cilexetil will be reviewed in this article.

Critical review of cancer risk associated with angiotensin receptor blocker therapy

The role of drugs in new cancer occurrence and cancer-related death is a major concern. Recently, a meta-analysis raised the possibility that angiotensin receptor blockers (ARBs) might have an adverse effect on patients. This generated a significant debate until the publication of two further meta-analyses, neither of which demonstrated an increased risk of new cancer occurrence or cancer-related death with the use of ARBs in patients with hypertension, heart failure, and/or nephropathy. This illustrates that the results of meta-analyses should be interpreted cautiously and critically as bias, such as selection bias, might lead to erroneous conclusions. Overall, the bulk of evidence today indicates that ARBs are not associated with increased cancer risk.

Neural degeneration in the retina of the streptozotocin-induced type 1 diabetes model

Diabetic retinopathy, a vision-threatening disease, has been regarded as a vascular disorder. However, impaired oscillatory potentials (OPs) in the electroretinogram (ERG) and visual dysfunction are recorded before severe vascular lesions appear. Here, we review the molecular mechanisms underlying the retinal neural degeneration observed in the streptozotocin-(STZ-) induced type 1 diabetes model. The renin-angiotensin system (RAS) and reactive oxygen species (ROS) both cause OP impairment and reduced levels of synaptophysin, a synaptic vesicle protein for neurotransmitter release, most likely through excessive protein degradation by the ubiquitin-proteasome system. ROS also decrease brain-derived neurotrophic factor (BDNF) and inner retinal neuronal cells. The influence of both RAS and ROS on synaptophysin suggests that RAS-ROS crosstalk occurs in the diabetic retina. Therefore, suppressors of RAS or ROS, such as angiotensin II type 1 receptor blockers or the antioxidant lutein, respectively, are potential candidates for neuroprotective and preventive therapies to improve the visual prognosis.

Effects of Manidipine and Delapril in Hypertensive Patients With Type 2 Diabetes Mellitus

To assess whether angiotensin-converting enzyme inhibitors and third-generation dihydropyridine calcium channel blockers ameliorate diabetic complications, we compared glomerular filtration rate (GFR; primary outcome), cardiovascular events, retinopathy, and neuropathy in 380 hypertensive type 2 diabetics with albuminuria <200 mg/min included in a multicenter, double-blind, placebo-controlled trial (DEMAND [Delapril and Manidipine for Nephroprotection in Diabetes]) and randomized to 3-year treatment with manidipine/delapril combination (10/30 mg/d; n=126), delapril (30 mg/d; n=127), or placebo (n=127). GFR was centrally measured by iohexol plasma clearance. Median monthly GFR decline (interquartile range [IQR]) was 0.32 mL/min per 1.73 m 2 (IQR: 0.16–0.50 mL/min per 1.73 m 2 ) on combined therapy, 0.36 mL/min per 1.73 m 2 (IQR: 0.18–0.53 mL/min per 1.73 m 2 ) on delapril, and 0.30 mL/min per 1.73 m 2 (IQR: 0.12–0.50 mL/min per 1.73 m 2 ) on placebo ( P =0.87 and P =0.53 versus combined therapy or delapril, respectively). Similar findings were observed when baseline GFR values were not considered for slope analyses. Albuminuria was stable in the 3 treatment groups. The hazard ratio (95% CI) for major cardiovascular events between combined therapy and placebo was 0.17 (0.04–0.78; P =0.023). Among 192 subjects without retinopathy at inclusion, the hazard ratio for developing retinopathy between combined therapy and placebo was 0.27 (0.07–0.99; P =0.048). Among 200 subjects with centralized neurological evaluation, the odds ratios for peripheral neuropathy at 3 years between combined therapy or delapril and placebo were 0.45 (0.24–0.87; P =0.017) and 0.52 (0.27–0.99; P =0.048), respectively. Glucose disposal rate decreased from 5.8±2.4 to 5.3±1.9 mg/kg per min on placebo ( P =0.03) but did not change on combined or delapril therapy. Treatment was well tolerated. In hypertensive type 2 diabetic patients, combined manidipine and delapril therapy failed to slow GFR decline but safely ameliorated cardiovascular disease, retinopathy, and neuropathy and stabilized insulin sensitivity.

Early-onset type 2 diabetes: high risk for premature diabetic retinopathy

AIM

To examine the relationship between early-onset type 2 diabetes (T2D) and retinopathy in relation to the burden, severity, the extent of its premature development and associated predictive risk factors.

METHODS

A cross sectional study using the hospital diabetes register and eye screening database to identify T2D subjects and to ascertain retinopathy severity. Early and later-onset cohort were defined as age of diagnosis <40 and >40 years respectively.

RESULTS

2516 subjects were identified of which 455 were diagnosed below 40 years. After 10 years of diagnosis, the prevalence of overall retinopathy was significantly higher in the early-onset cohort (p < 0.05). For significant retinopathy (SigDR), there was a non-significant trend of higher prevalence with increasing diabetes duration in the early-onset cohort. The rate of increase for SigDR was greater in the early-onset cohort who experienced similar burden of SigDR up to 20 years earlier than the later-onset cohort. Hypertension (p < 0.05), suboptimal glycaemic control (p < 0.05) and long diabetes duration (p < 0.05) were associated with risk of retinopathy whilst lower age of diagnosis and dyslipidaemia were not significant predictive factors.

CONCLUSIONS

Early-onset T2D subjects are at risk of developing premature retinopathy driven predominantly by hypertension and prolonged exposure to suboptimal diabetes control.

Olmesartan ameliorates peripheral nerve dysfunction in Zucker diabetic fatty rats

OBJECTIVE

Angiotensin (ANG) II type 1 receptor (AT1R) blockers have neuroprotective effects against neuronal lesions. The present study examines whether the AT1R blocker olmesartan improves peripheral nerve dysfunction in rats with type 2 diabetes.

METHODS

Fourteen-week-old male type 2 diabetic Zucker diabetic fatty (ZDF) rats were orally administered with olmesartan (6 mg/kg per day; n = 7) or not treated (n = 7) and then followed up for nine weeks. Age-matched and sex-matched nondiabetic lean rats served as controls (n = 7).

RESULTS

Olmesartan for 9 weeks did not influence blood glucose and A1c levels that were higher in untreated ZDF (U-ZDF) rats than in control rats. In U-ZDF rats, myelinated fiber density and myelin areas of myelinated fibers in peroneal nerves significantly increased and decreased, respectively, and the intraepidermal nerve fiber density (IENFD) of footpad skin tended to decrease. The U-ZDF rats developed mechanical hyperalgesia, thermal hypoalgesia and slower sensory and motor nerve conduction in the sciatic-tibial nerves. Olmesartan increased myelin areas and IENFD and ameliorated sensory nerve conduction deficits. These beneficial effects of olmesartan were associated with ANG II and insulin receptor upregulation in sensory neurons as well as deactivation of Erk1/2 in sciatic nerves.

CONCLUSION

Olmesartan appears to improve the structure and function of small and large nerves and upregulate ANG II and insulin receptors in sensory neurons of rats with type 2 diabetes.

Aliskiren reduces vascular pathology in diabetic retinopathy and oxygen-induced retinopathy in the transgenic (mRen-2)27 rat

AIM/HYPOTHESIS

We examined whether the renin inhibitor, aliskiren, provides similar or greater protection than ACE inhibition from non-proliferative diabetic retinopathy and from the proliferative neoangiogenesis of oxygen-induced retinopathy.

METHODS

Transgenic (mRen-2)27 rats, which overexpress mouse renin and angiotensin in extra-renal tissues, were studied. For diabetic studies, non-diabetic, diabetic (streptozotocin, 55 mg/kg), diabetic + aliskiren (10 mg kg(-1) day(-1), pump), or diabetic + lisinopril (10 mg kg(-1) day(-1), drinking water) rats were evaluated over 16 weeks. For oxygen-induced retinopathy studies, rats were exposed to 80% oxygen (22 h/day) from postnatal days 0 to 11, and then room air from postnatal days 12 to 18. Aliskiren (10 or 30 mg kg(-1) day(-1), pump) or lisinopril (10 mg kg(-1) day(-1), drinking water) was administered during retinopathy development between postnatal days 12 and 18.

RESULTS

Systolic BP in diabetic (mRen-2)27 rats was reduced with 10 mg kg(-1) day(-1) aliskiren, but only lisinopril normalised systolic blood pressure. In diabetic (mRen-2)27 rats, 10 mg kg(-1) day(-1) aliskiren and lisinopril reduced retinal acellular capillaries and leucostasis to non-diabetic levels. In oxygen-induced retinopathy, neoangiogenesis and retinal inflammation (leucostasis, ED-1 immunolabelling) were partially reduced by 10 mg kg(-1) day(-1) aliskiren and normalised by 30 mg kg(-1) day(-1) aliskiren, whereas lisinopril normalised neoangiogenesis and reduced leucostasis and ED-1 immunolabelling. Aliskiren and lisinopril normalised retinal vascular endothelial growth factor expression; however, only aliskiren reduced intercellular adhesion molecule-1 to control levels.

CONCLUSIONS/INTERPRETATION

Aliskiren provided similar or greater retinal protection than ACE inhibition and may be a potential treatment for diabetic retinopathy.

Anti-inflammatory therapy for diabetic retinopathy

Diabetic retinopathy (DR) is one of the most common complications of diabetes. This devastating disease is a leading cause of blindness in people of working age in industrialized countries and affects the daily lives of millions of people. Despite tight glycemic control, blood pressure control and lipid-lowering therapy, the number of DR patients keeps growing and therapeutic approaches are limited. Moreover, there are significant limitations and side effects associated with the current therapies. Thus, there is a great need for development of new strategies for prevention and treatment of DR. Studies have shown that DR has prominent features of chronic, subclinical inflammation. This article focuses on the role of inflammation in DR and summarizes the progress of studies of anti-inflammatory strategies for DR.

New approaches to the treatment of diabetic retinopathy

Diabetic retinopathy (DR) is a leading cause of visual impairment in working age in industrialized countries. It is classified as non-proliferative (mild, moderate or severe) and proliferative, with diabetic macular oedema potentially developing at any of these stages. The prevalence and incidence of DR increase with diabetes duration and worsening of metabolic and blood pressure control. Current approaches to prevent and/or treat DR include optimized control of blood glucose and blood pressure and screening for early identification of high-risk, although still asymptomatic, retinal lesions. Results from recent clinical trials suggest a role for blockers of the renin-angiotensin system (angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers) and for fenofibrate in reducing progression and/or inducing regression of mild-to-moderate non-proliferative DR. Intravitreal administration of anti-vascular endothelial growth factor (VEGF) agents was shown to reduce visual loss in more advanced stages of DR, especially in macular oedema.

An overview of candesartan in clinical practice

Hypertension is a major risk factor for coronary heart disease, stroke, heart failure and renal disease. The Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure 7 defined hypertension as a blood pressure of more than 140/90 mmHg and recommended to initiate treatment with a two-drug combination for stage 2 hypertension (blood pressure of 160-179/100-109 mmHg). The need for drug combinations is clear from a patient and physician perspective as they provide more effective blood pressure lowering, reduce pill burden, improve compliance and decrease hypertension-related morbidity and mortality. Angiotensin II receptor blocker therapy has been proven to be well tolerated and effective in the management of hypertension, chronic heart failure with left ventricular dysfunction and the prevention and progression of diabetic renal disease. Blockers of the renin-angiotensin system are an important component of antihypertensive combination therapy. Thiazide-type diuretics are usually added to increase the blood pressure lowering efficacy. Fixed drug-drug combinations of both principles, such as candesartan/hydrochlorothiazide, are highly effective in lowering blood pressure while providing improved compliance, a good tolerability and largely neutral metabolic profile. In this article, we review the literature for the role of candesartan-based therapy for hypertension, stroke, diabetes mellitus and heart failure.

ACE2 and Ang-(1-7) confer protection against development of diabetic retinopathy

Despite evidence that hyperactivity of the vasodeleterious axis (ACE/angiotensin II (Ang II)/AT1 receptor) of the renin-angiotensin system (RAS) is associated with the pathogenesis of diabetic retinopathy (DR) use of the inhibitors of this axis has met with limited success in the control of this pathophysiology. We investigated the hypothesis that enhancing the local activity of the recently established protective axis of the RAS, ACE2/Ang-(1-7), using adeno-associated virus (AAV)-mediated gene delivery of ACE2 or Ang-(1-7) would confer protection against diabetes-induced retinopathy. Genes expressing ACE2 and Ang-(1-7) were cloned in AAV vector. The effects of ocular AAV-ACE2/Ang-(1-7) gene transfer on DR in diabetic eNOS(-/-) mice and Sprague-Dawley (SD) rats were examined. Diabetes was associated with approximately tenfold and greater than threefold increases in the ratios of ACE/ACE2 and AT1R/Mas mRNA levels in the retina respectively. Intraocular administration of AAV-ACE2/Ang-(1-7) resulted in significant reduction in diabetes-induced retinal vascular leakage, acellular capillaries, infiltrating inflammatory cells and oxidative damage in both diabetic mice and rats. Our results demonstrate that DR is associated with impaired balance of retinal RAS. Increased expression of ACE2/Ang-(1-7) overcomes this imbalance and confers protection against DR. Thus, strategies enhancing the protective ACE2/Ang-(1-7) axis of RAS in the eye could serve as a novel therapeutic target for DR.

[Clinical and pharmacological factors related to the requirements of laser photocoagulation in patients with diabetic nephropathy due to type 2 diabetes mellitus]

BACKGROUND AND OBJECTIVE

Diabetic retinopathy is a microvascular complication of diabetes mellitus whose prevalence is closely related to the presence of nephropathy and hypertension. The aim was to study clinical and pharmacological factors that are associated with an increased need for laser photocoagulation in patients with diabetic nephropathy and retinopathy.

PATIENTS AND METHODS

Cross sectional study of 63 patients followed in the Diabetic Nephropathy consultation. Patients were divided into 2 groups according to whether or not previously have received photocoagulation. In each subgroup were studied demographic variables, anthropometric, laboratory, cardiovascular risk factors and treatment received by each patient for the control of hypertension, diabetes and others diseases.

RESULTS

We observed that the group had received photocoagulation had more years of diabetes evolution, more history of cardiovascular disease and a lower creatinine clearance. Similarly, the percentage of patients treated with carvedilol was significantly higher in the subgroup who had not received photocoagulation while the percentage of patients treated with beta-blockers was significantly higher in the subgroup that received photocoagulation; no significant differences was observed in the degree of control blood pressure.

CONCLUSIONS

Clinical and pharmacological factors related to the requirements of laser photocoagulation were years of diabetes evolution, history of cardiovascular disease, the stage of kidney disease and the treatment with beta-blockers.

Effects of telmisartan, irbesartan, valsartan, candesartan, and losartan on cancers in 15 trials enrolling 138,769 individuals

BACKGROUND

Angiotensin-converting enzyme inhibitors (ACEi) and angiotensin II receptor blockers (ARBs) reduce cardiovascular disease (CVD) events, but a recent meta-analysis of selected studies suggested that ARBs may increase cancer risks.

OBJECTIVE

Candesartan, irbesartan, telmisartan, valsartan, and losartan were assessed for incident cancers in 15 large parallel long-term multicenter double-blind clinical trials of these agents involving 138,769 participants.

PATIENTS AND METHODS

Individuals at high CVD risk were randomized to telmisartan (three trials, n=51,878), irbesartan (three trials, n=14,859), valsartan (four trials, n=44,264), candesartan (four trials, n=18,566), and losartan (one trial, n=9193) and followed for 23-60 months. Incident cancer cases were compared in patients randomized to ARBs versus controls. In five trials (n=42,403), the ARBs were compared to ACEi and in 11 trials (n=63,313) to controls without ACEi. In addition, in seven trials (n=47,020), the effect of ARBs with ACEi was compared to ACEi alone and in two trials ARBs with ACEi versus ARB alone (n=25,712).

RESULTS

Overall, there was no excess of cancer incidence with ARB therapy compared to controls in the 15 trials [4549 (6.16%) cases of 73,808 allocated to ARB versus 3856 (6.31%) of 61 106 assigned to non-ARB controls; odds ratio (OR) 1.00, 95% confidence interval (CI) 0.95-1.04] overall or when individual ARBs were examined. ORs comparing combination therapy with ARB along with ACEi versus ACEi was 1.01 (95% CI 0.94-1.10), combination versus ARB alone 1.02 (95% CI 0.91-1.13), ARB alone versus ACEi alone 1.06 (95% CI 0.97-1.16) and ARB versus placebo/control without ACEi 0.97 (95% CI 0.91-1.04). There was no excess of lung, prostate or breast cancer, or overall cancer deaths associated with ARB treatment.

CONCLUSION

There was no significant increase in the overall or site-specific cancer risk from ARBs compared to controls.

Diabetic retinopathy: pathogenic mechanisms and current treatments

Since diabetes is now a global epidemic, the incidence of retinopathy, a leading cause of blindness in patients aged 20-74 years, is also expected to rise to alarming levels. The risk of development and progression of diabetic retinopathy is closely associated with the type and duration of diabetes, blood glucose, blood pressure and possibly lipids. It is an unmet medical need that can lead to severe and irreversible loss of vision in people of working age worldwide. The aim of this review is to give an overview of the clinical and anatomical changes during the progression of retinopathy, the underlying pathogenic mechanisms that link hyperglycemia with retinal tissue damage, current treatments, and the emerging pharmacological therapies for this sight-threatening complication of diabetes.

Exposure to candesartan during the first trimester of pregnancy in type 1 diabetes: experience from the placebo-controlled DIabetic REtinopathy Candesartan Trials

AIMS/HYPOTHESIS

The teratogenic consequences of angiotensin-converting enzyme inhibitors angiotensin receptor blockers (ARBs) during the second and third trimesters of pregnancy are well described. However, the consequences of exposure during the first trimester are unclear, especially in diabetes. We report the experience from DIRECT (DIabetic REtinopathy and Candesartan Trials), three placebo-controlled studies designed to examine the effects of an ARB, candesartan, on diabetic retinopathy.

METHODS

Over 4 years or longer, 178 normotensive women with type 1 diabetes (86 randomised to candesartan, 32 mg once daily, and 92 assigned to placebo) became pregnant (total of 208 pregnancies).

RESULTS

More than half of patients were exposed to candesartan or placebo prior to or in early pregnancy, but all discontinued it at an estimated 8 weeks from the last menstrual period. Full-term pregnancies (51 vs 50), premature deliveries (21 vs 27), spontaneous miscarriages (12 vs 15), elective terminations (15 vs 14) and other outcomes (1 vs 2) were similar in the candesartan and placebo groups. There were two stillbirths and two 'sick babies' in the candesartan group, and one stillbirth, eight 'sick babies' and one cardiac malformation in the placebo group.

CONCLUSIONS/INTERPRETATION

The risk for fetal consequences of ARBs in type 1 diabetes may not be high if exposure is clearly limited to the first trimester. Long-term studies in fertile women can be conducted with ARBs during pregnancy, provided investigators diligently stop their administration upon planning or detection of pregnancy.

TRIAL REGISTRATION

ClinicalTrials.gov DIRECT-Prevent 1 NCT00252733; DIRECT-Protect 1 NCT00252720; DIRECT-Protect 2 NCT00252694.

FUNDING

The study was funded jointly by AstraZeneca and Takeda.

Five-year visual outcome following laser photocoagulation of diabetic macular oedema

OBJECTIVE

To evaluate the 5-year visual outcome associated with laser photocoagulation treatment of diabetic macular oedema (DMO), and to investigate the relationship between systemic factors and visual outcomes in a real-life setting.

METHODS

The mean annual visual outcomes and systemic parameters of 100 consecutive subjects with type 2 diabetes who underwent the first session of focal/grid macular laser photocoagulation for clinically significant macular oedema between 2003 and 2004 were collected retrospectively and compared with the outcomes of the laser arm of the Diabetic Retinopathy Clinical Research Network (DRCRN trial comparing intravitreal triamcinolone acetonide injection with laser photocoagulation treatment for DMO). The primary outcome measures included the mean change in visual acuity (VA) in 5 years and the influence of systemic factors on final visual outcome.

RESULTS

The mean change in VA at 5 years was -5.23 in a real-life setting for an inner city population. The 3-year outcome was inferior to the clinical trial results with more people gaining vision (≥15 letter gain) in the DRCRN group compared with this cohort (26 vs 9%). Furthermore, three times more patients lost vision (>15 letter loss) in the real-life setting of this cohort compared with the clinical trial results of the DRCRN group (27 vs 8%, respectively).

CONCLUSIONS

The visual outcomes and the control of systemic factors of patients with DMO in this cohort were inferior to those recruited for the clinical trial involving the DRCRN group.

Angiotensin receptor blockers and angiogenesis: clinical and experimental evidence

Angiotensin II type 1 receptor antagonists [ARBs (angiotensin receptor blockers)] are indicated for BP (blood pressure)-lowering, renal protection and cardioprotection in patients unable to tolerate ACEIs (angiotensin-converting enzyme inhibitors). A recent meta-analysis revealed an association between ARBs and tumour development, possibly due to enhancement of angiogenesis. However, published evidence is conflicting on the effects of ARBs on angiogenesis or the expansion of the existing vascular network. ARBs have been shown to exert primarily anti-angiogenic effects in basic science studies of cancer, retinopathy, peripheral artery disease and some models of cardiovascular disease. In animal and cellular models of myocardial infarction and stroke, however, ARB administration has been associated with robust increases in vascular density and improved recovery. The aim of the present review is to examine the angiogenic effects of ARBs in animal and cellular models of relevant disease states, including proposed molecular mechanisms of action of ARBs and the clinical consequences of ARB use.

Angiotensin receptor blockers and risk of myocardial infarction: meta-analyses and trial sequential analyses of 147 020 patients from randomised trials

OBJECTIVES

To evaluate the cardiovascular outcomes and other outcomes associated with angiotensin receptor blockers.

DESIGN

Systematic review of randomised controlled trials with meta-analysis and trial sequential analysis (TSA).

DATA SOURCES AND STUDY SELECTION

Pubmed, Embase, and CENTRAL searches for randomised clinical trials, until August 2010, of angiotensin receptor blockers compared with controls (placebo/active treatment) that enrolled at least 100 participants and had a follow-up of at least one year.

DATA EXTRACTION

Myocardial infarction, death, cardiovascular death, angina pectoris, stroke, heart failure, and new onset diabetes.

RESULTS

37 randomised clinical trials included 147,020 participants and had a total follow-up of 485,166 patient years. When compared with controls (placebo/active treatment), placebo, or active treatment, angiotensin receptor blockers were not associated with an increase in the risk of myocardial infarction (relative risk 0.99, 95% confidence interval 0.92 to 1.07), death, cardiovascular death, or angina pectoris. Compared with controls, angiotensin receptor blockers were associated with a reduction in the risk of stroke (0.90, 0.84 to 0.98), heart failure (0.87, 0.81 to 0.93), and new onset diabetes (0.85, 0.78 to 0.93), with similar results when compared with placebo or with active treatment. Based on trial sequential analysis, there is no evidence even for an average 5.0-7.5% (upper confidence interval 5-11%) relative increase in myocardial infarction (absolute increase of 0.3%), death, or cardiovascular death with firm evidence for relative risk reduction of stroke (at least 1%, average 10%) (compared with placebo only), heart failure (at least 5%, average 10%), and new onset diabetes (at least 4%, average 10%) with angiotensin receptor blockers compared with controls.

CONCLUSIONS

This large and comprehensive analysis produced firm evidence to refute the hypothesis that angiotensin receptor blockers increase the risk of myocardial infarction (ruling out even a 0.3% absolute increase). Compared with controls, angiotensin receptor blockers reduce the risk of stroke, heart failure, and new onset diabetes.

How does hypertension affect your eyes?

Hypertension has profound effects on various parts of the eye. Classically, elevated blood pressure results in a series of retinal microvascular changes called hypertensive retinopathy, comprising of generalized and focal retinal arteriolar narrowing, arteriovenous nicking, retinal hemorrhages, microaneurysms and, in severe cases, optic disc and macular edema. Studies have shown that mild hypertensive retinopathy signs are common and seen in nearly 10% of the general adult non-diabetic population. Hypertensive retinopathy signs are associated with other indicators of end-organ damage (for example, left ventricular hypertrophy, renal impairment) and may be a risk marker of future clinical events, such as stroke, congestive heart failure and cardiovascular mortality. Furthermore, hypertension is one of the major risk factors for development and progression of diabetic retinopathy, and control of blood pressure has been shown in large clinical trials to prevent visual loss from diabetic retinopathy. In addition, several retinal diseases such as retinal vascular occlusion (artery and vein occlusion), retinal arteriolar emboli, macroaneurysm, ischemic optic neuropathy and age-related macular degeneration may also be related to hypertension; however, there is as yet no evidence that treatment of hypertension prevents vision loss from these conditions. In management of patients with hypertension, physicians should be aware of the full spectrum of the relationship of blood pressure and the eye.

Progression and regression: distinct developmental patterns of diabetic retinopathy in patients with type 2 diabetes treated in the diabetes care system west-friesland, the Netherlands

OBJECTIVE

To identify distinct developmental patterns of diabetic retinopathy (DR) and assess the risk factor levels of patients in these clusters.

RESEARCH DESIGN AND METHODS

A cohort of 3,343 patients with type 2 diabetes mellitus (T2DM) monitored and treated in the Diabetes Care System West-Friesland, the Netherlands, was followed from 2 to 6 years. Risk factors were measured, and two-field fundus photographs were taken annually and graded according to the EURODIAB study group. Latent class growth modeling was used to identify distinct developmental patterns of DR over time.

RESULTS

Five clusters of patients with distinct developmental patterns of DR were identified: A, patients without any signs of DR (88.9%); B, patients with a slow regression from minimal background to no DR (4.9%); C, patients with a slow progression from minimal background to moderate nonproliferative DR (4.0%); D, patients with a fast progression from minimal or moderate nonproliferative to (pre)proliferative or treated DR (1.4%); and E, patients with persistent proliferative DR (0.8%). Patients in clusters A and B were characterized by lower risk factor levels, such as diabetes duration, HbA(1c), and systolic blood pressure compared with patients in progressive clusters (C-E).

CONCLUSIONS

Clusters of patients with T2DM with markedly different patterns of DR development were identified, including a cluster with regression of DR. These clusters enable a more detailed examination of the influence of various risk factors on DR.

Diabetic retinopathy - An update

Management of diabetes should involve both systemic and ocular aspects. Control of hyperglycemia, hypertension and dyslipidemia are of major role in the management of diabetic retinopathy. In the ocular part; laser treatment remains the cornerstone of treatment of diabetic macular edema (focal/grid), severe non-proliferative and proliferative diabetic retinopathy (panretinal photocoagulation). There is a strong support to combination therapy. Using one or two intravitreal injections such as anti-VEGF and or steroid to reduce central macular thickness followed by focal or grid laser to give a sustained response may offer an alternative to treatment in diabetic macular edema. Anti-VEGF were found to be effective as an adjunct therapy in proliferative diabetic retinopathy patient who is going to have vitrectomy for vitreous hemorrhage with neovascularization, panretinal photocoagulation, and other ocular surgery such as cases with neovascular glaucoma and cataract with refractory macular edema.

Advances in the treatment of diabetic retinopathy

Diabetic retinopathy, the most common long-term complication of diabetes mellitus, remains one of the leading causes of blindness worldwide. Strict metabolic control, tight blood pressure control, laser photocoagulation, and vitrectomy remain the standard care for diabetic retinopathy. Focal/grid photocoagulation is a better treatment than intravitreal triamcinolone acetonide in eyes with diabetic macular edema and should be considered as the first-line therapeutic option. The current evidence suggests that intravitreal triamcinolone acetonide or anti-vascular endothelial growth factor agents result in a temporary improvement of visual acuity and a short-term reduction in central macular thickness in patients with refractory diabetic macular edema and are an effective adjunctive treatments to laser photocoagulation or vitrectomy. However, triamcinolone is associated with risks of elevated intraocular pressure and cataract. Vitrectomy with the removal of the posterior hyaloid without internal limiting membrane peeling seems to be effective in eyes with persistent diffuse diabetic macular edema, particularly in eyes with associated vitreomacular traction. Emerging therapies include islet cell transplantation, fenofibrate, ruboxistaurin, pharmacologic vitreolysis, rennin-angiotensin system blockers, and peroxisome proliferator-activated receptor gamma agonists.

Microvascular complications and risk factors in patients with type 2 diabetes

AIM

To conduct a prospective study in patients with type 2 diabetes mellitus (T2DM) with no microvascular complications, analyzing the association between various baseline risk factors and development of microvascular complications at follow-up.

METHODS

A prospective, observational study in 376 patients with T2DM enrolled in 2004. The clinical end-point was urinary albumin excretion (UAE) > 30mg/24h and/or presence of retinopathy at follow-up in 2007. Baseline variables included age, gender, duration of T2DM, fasting plasma glucose, glycated hemoglobin (HbA(1c)), systolic and diastolic blood pressure, body weight, height, body mass index, waist circumference, total cholesterol, triglycerides, high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), high sensitive C-reactive protein (hs-CRP), fibrinogen, UAE, creatinine, smoking status, exercise, alcohol consumption, use of hypoglycemic and lipid-lowering drugs, antihypertensive medications, and other data related to family history of diabetes and risk factors.

RESULTS

Ninety-five subjects (25.2%) developed a microvascular complication at the end of the follow-up period. In logistic regression analyses, the main independent risk factors were UAE >12mg/24h (odds ratio [OR]: 6.12; P=.000), hs-CRP> 3mg/L (OR: 3.00; P=.004), and hypertension (OR: 2.43; P=.023).

CONCLUSIONS

UAE levels higher than 12mg/24h, hs-CRP >3mg/L, and presence of hypertension were all independent risk factors for development of microvascular complications in patients with T2DM studied.

Higher levels of prorenin predict development of diabetic retinopathy in patients with type 2 diabetes

The aim was to determine whether serum prorenin levels affect the development of diabetic retinopathy (DR) in type 2 diabetes. Baseline serum prorenin levels were measured in 196 patients (85 males, 111 females) with type 2 diabetes without DR using the antibody-activating direct prorenin assay. The fundi were checked regularly. The participants were divided into two groups based on the serum prorenin levels (high and low). We used Kaplan—Meyer analysis to detect differences in the development of DR between the two groups within the same gender. Kaplan—Meyer analysis showed that males with a high serum prorenin level tended to develop DR earlier and more frequently than males with a low prorenin level ( p = 0.004 by the log rank test). However, there was no difference in the development of DR between high and low groups in females ( p = 0.58). Serum prorenin levels in males with type 2 diabetes could be a new prognostic indicator of the development of DR.

Targets of chymase inhibitors

INTRODUCTION

Chymase converts angiotensin I to angiotensin II and it can also convert precursors of TGF-β and MMP-9 to their active forms. Therefore, diseases related to angiotensin II TGF-β, and MMP-9 could potentially be treated with chymase inhibitors.

AREAS COVERED

This review discusses the appropriate targets and safety of chymase inhibitors. Six diseases with notable mortality or morbidity as targets of chymase inhibitors are focused on; abdominal aortic aneurysms (AAAs), nephropathy and retinopathy, cardiomyopathy, nonalcoholic steatohepatitis (NASH), organ fibrosis and intestinal diseases.

EXPERT OPINION

If chymase inhibition proves to be a useful strategy for the attenuation of angiotensin II, TGF-β and MMP-9 in vivo, the application of chymase inhibitors is likely to become widespread in various diseases in the clinical setting. Chymase inhibitors are anticipated not to interfere with the homeostasis of resting tissues, that is, those not affected by injury or inflammation.

Does renin-angiotensin system blockade have a role in preventing diabetic retinopathy? A clinical review

Diabetes management has increasingly focused on the prevention of macrovascular disease, in particular for type 2 diabetes. Diabetic retinopathy, one of the main microvascular complications of diabetes, is also an important public health problem. Much of the care invested in retinopathy relates to treatment rather than prevention of disease. Tight glycaemic and blood pressure control helps to reduce the risk of retinopathy, but this is not easy to achieve in practice and additional treatments are needed for both primary and secondary prevention of retinopathy. A renin-angiotensin system (RAS) has been identified in the eye and found to be upregulated in retinopathy. This has led to specific interest in the role of RAS blockade in retinopathy prevention. The recent DIRECT programme assessed use of the angiotensin receptor blocker (ARB) candesartan in type 1 and type 2 diabetes. Although the primary trial end-points were not met, there was a clear trend to less severe retinopathy with RAS blockade. A smaller trial, RASS, reported reduced retinopathy progression in type 1 diabetes from RAS blockade with both the ARB losartan and the angiotensin converting enzyme (ACE) inhibitor enalapril. The clinical implications of these new data are discussed.

The contribution of hypertension to diabetic nephropathy and retinopathy: the role of inflammation and oxidative stress

Diabetes and hypertension frequently coexist and constitute the most notorious combination for the pathogenesis of diabetic nephropathy and retinopathy. Large clinical trials have clearly demonstrated that tight control of glycemia and/or blood pressure significantly reduces the incidence and progression of diabetic retinopathy (DR) and nephropathy. However, the mechanism by which hypertension interacts with diabetes to induce and/or exacerbate nephropathy and retinopathy is very unclear. Substantial evidence implicates the involvement of chronic inflammation and oxidative stress in the pathogenesis of DR and nephropathy. In addition, hypertension causes oxidative stress and inflammation in the kidney and retina. In the present review, we summarized data obtained from our research along with those from other groups to better understand the role of hypertension in the pathogenesis of diabetic nephropathy and retinopathy. It is suggested that oxidative stress and inflammation may be common denominators of kidney and retinal damage in the concomitant presence of diabetes and hypertension.